Merge pull request swiftlang#32337 from LucianoPAlmeida/SR-12955-avoid-error-type-diag

[SR-12955] [Sema] Don't diagnose invalid conversion if fnType has error

Author: LucianoPAlmeida

lib/AST/Type.cpp

@@ -2208,6 +2208,16 @@ getObjCObjectRepresentable(Type type, const DeclContext *dc) {
 static std::pair<ForeignRepresentableKind, ProtocolConformance *>
 getForeignRepresentable(Type type, ForeignLanguage language,
                         const DeclContext *dc) {
+  // Local function that simply produces a failing result.
+  auto failure = []() -> std::pair<ForeignRepresentableKind,
+                                   ProtocolConformance *> {
+    return { ForeignRepresentableKind::None, nullptr };
+  };
+  
+  // If type has an error let's fail early.
+  if (type->hasError())
+    return failure();
+  
   // Look through one level of optional type, but remember that we did.
   bool wasOptional = false;
   if (auto valueType = type->getOptionalObjectType()) {
@@ -2222,12 +2232,6 @@ getForeignRepresentable(Type type, ForeignLanguage language,
       return { representable, nullptr };
   }
 
-  // Local function that simply produces a failing result.
-  auto failure = []() -> std::pair<ForeignRepresentableKind,
-                                   ProtocolConformance *> {
-    return { ForeignRepresentableKind::None, nullptr };
-  };
-
   // Function types.
   if (auto functionType = type->getAs<FunctionType>()) {
     // Cannot handle throwing functions.

lib/Sema/TypeCheckType.cpp

@@ -2675,6 +2675,10 @@ Type TypeResolver::resolveASTFunctionType(
   }
 
   auto fnTy = FunctionType::get(params, outputTy, extInfo);
+  
+  if (fnTy->hasError())
+    return fnTy;
+
   // If the type is a block or C function pointer, it must be representable in
   // ObjC.
   switch (representation) {

test/expr/closure/inference.swift

@@ -73,3 +73,8 @@ let cc = SR8563 { (_: (Int)) in }
 
 cc((1)) // Ok
 cc(1) // Ok
+
+// SR-12955
+func SR12955() {
+  let f: @convention(c) (T) -> Void // expected-error {{cannot find type 'T' in scope}}
+}